The headers of modern combine harvesters mostly have a width of many meters, so that a combine harvester with mounted header is too wide to use public roads. A header trailer is therefore required in order to transport the header separately from the combine harvester on public roads.
Known from DD 301 470 A7 is a header trailer with a chassis and a support saddle mounted on the chassis which is shaped so as to support a header placed on it stably during transportation. The shape of the support saddle is adapted to the type of header which is to be transported. In order to allow a header of a different type to be transported, it is suggested that an additional support be used which can be placed on the support saddle and which is adapted to the shape of the second type of header in order to support the latter stably. Although such a trailer makes it possible to transport different types of header, a specific intermediate support is required for each additional type. Each type of header can only be transported in a single, predetermined orientation.
EP 0 045 039 B1 discloses a header trailer in which a support saddle is composed of several components which can be moved in relation to one another. Thus, the support saddle comprises, on the one hand, several carrying rails which can be pivoted between different positions in which headers of different types are, depending on the type, supported by one, the other or both carrying rails, and on the other hand a seating part with a fork-shaped receiving recess open at the top which can be raised in order to support a crossbar of the header or lowered in order to allow a rear section of the header to be placed in a supporting pocket adjacent to the receiving recess.
Although such a header trailer does not require any intermediate support in order for different types of headers to be transported, due to the construction design of the trailer the types of headers which can be transported are fixed from the outset. Also, each type of header can only be accommodated in a fixed orientation in relation to the trailer. In laden condition an adjustment of the moveable components of the support saddle is not possible.
U.S. Pat. No. 4,834,598 discloses a header trailer in which a horizontally adjustable stop is attached to one end of a crossmember of the chassis and an arm which is vertically and transversely adjustable is attached to the other end in order to allow different types of header to be supported. Here too, as a rule, for each type of header only one position of the arm exists in which the header is stably supported, and the position of the header in relation to the chassis is fixed.
All of these known header trailers can be adjusted in their form so that a particular combine harvester can set down a header associated with it in a secure storage position and pick it up again from the trailer. However, they fail to take into account that operators who have several combine harvesters in use may wish to use the same header on different combine harvesters of different types. The problem which arises here is that the intake channels of the combine harvesters to which the headers need to be fitted can, in different types, have different orientations. Accordingly, the orientations in which the different types of combine harvester can gently set down the same header on a transport trailer, or pick it up again, may differ.
Regardless of the potentially different orientations of the intake channels further problems may result from the fact that in order to attach a header the intake channel must be introduced into a space between a trailer wheel and the header, and that the place requirement of the intake channel in this space may vary from one model to another. Generally, it is desired to locate the centre of gravity of the header as low as possible on the trailer and as close as possible to a longitudinal centre plane of the trailer, in order to achieve stable support of the header and a good handling of the trailer. If at the same time the insertion space for the intake channel is to be made as wide as possible, impairments have to be accepted concerning the position of the centre of gravity. A further problem results from the fact that the lateral overhang which the header may have over the edge of the trailer is subject to limitations by law. If the header is placed off-centre so as to make the space for the intake channel wide, the side of the header opposite to the intake channel may have an inadmissibly wide overhang.